Airflow control system and methods thereof

ABSTRACT

A system and method of an airflow control system for a vehicle is described herein. The airflow control system (100) includes an airflow housing (120) defining an airflow passageway (125) extending between a bypass opening (122) and an intake outlet (124). The airflow housing also defines a duct opening (126) positioned between the bypass opening (122) and the intake outlet (124). The intake outlet (124) may be in fluid communication with an engine intake (12) of the vehicle such that air passes from the bypass opening (122) and/or the duct opening (126) to the engine intake (12). The airflow control system (100) also includes a movable duct (160) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the duct opening (126) and into the engine intake (12), and further includes a bypass door (140) movably connected to the airflow housing (120) to selectively allow or prevent air passage through the bypass opening (122) and into the engine intake (12).

RELATED APPLICATION

This application is a U.S. National Stage Application of InternationalApplication No. PCT/US2018/060092 filed 9 Nov. 2018, which was publishedin English on 16 May 2019 as International Publication No. WO2019/094765 A1 which claims the benefit under 35 U.S.C. 119(e) of U.S.Provisional Application No. 62/584,387 filed 10 Nov. 2017, and entitledAIRFLOW CONTROL SYSTEM AND METHODS THEREOF, all of which areincorporated herein by reference in their entirety.

FIELD OF THE DISCLOSURE

The disclosure herein relates generally to airflow control systems foruse with, for example, vehicles and other equipment. Specifically,airflow control systems that include multiple airflow paths that operatein conjunction with one another.

SUMMARY

Airflow control systems for vehicles and related methods are describedherein. In one or more embodiments, the airflow control systems includemultiple movable structures to allow or prevent air from traveling intoan engine intake. For example, the airflow control system may include amovable duct that provides a passage for air to be filtered beforeentering the engine intake and a bypass door that provides a passage forair to enter the engine intake without filtering. Further, the movableduct and the bypass door may operate in conjunction such that each moveat the same time in an inverse direction of one another (e.g., one movesfrom open to closed while the other moves from closed to open). Furtheryet, the motion of both the movable duct and the bypass door may becarried out by a single actuator.

An illustrative airflow control system may include an airflow housing, amovable duct, and a bypass door. The airflow housing may define anairflow passageway extending between a bypass opening and an intakeoutlet. The airflow housing may further define a duct opening positionedbetween the bypass opening and the intake outlet. The intake outlet maybe in fluid communication with an engine intake of the vehicle such thatair passes from the bypass opening and/or the duct opening to the engineintake. The movable duct may be movably connected to the airflow housingto selectively allow or prevent air passage through the duct opening andinto the engine intake. The bypass door may be movably connected to theairflow housing to selectively allow or prevent air passage through thebypass opening and into the engine intake.

In one or more embodiments of the airflow control system as describedherein, movement of the movable duct is interrelated to movement of thebypass door.

In one or more embodiments of the airflow control system as describedherein, the movable duct is movable between a duct open position toallow air to pass through the duct opening and a duct closed position toprevent air from passing through the duct opening, and wherein thebypass door is movable between a bypass open position to allow air topass through the bypass opening and a bypass closed position to preventair from passing through the bypass opening.

In one or more embodiments of the airflow control system as describedherein, the movable duct moves from the duct open position to the ductclosed position when the bypass door moves from the bypass closedposition to the bypass open position, and wherein the movable duct movesfrom the duct closed position to the duct open position when the bypassdoor moves from the bypass open position to the bypass closed position.

In one or more embodiments of the airflow control system as describedherein, the movable duct is in the duct open position when the bypassdoor is in the bypass closed position, and wherein the movable duct isin the duct closed position when the bypass door is in the bypass openposition.

In one or more embodiments of the airflow control system as describedherein, at least one of the bypass opening and the duct opening isalways at least partially open.

In one or more embodiments of the airflow control system as describedherein, the airflow control system may also include an actuatorconfigured to move both the bypass door and the movable duct.

In one or more embodiments of the airflow control system as describedherein, the airflow control system may also include a first actuatorconfigured to move the bypass door and a second actuator configured tomove the movable duct, wherein the first actuator is different than thesecond actuator.

In one or more embodiments of the airflow control system as describedherein, the airflow control system may also include an actuator coupledto the airflow housing and comprising a linear drive shaft configured toextend and retract in a linear direction and a bypass drive linkageextending between a first end portion and a second end portion, whereinthe first end portion of the bypass drive linkage is pivotally connectedto the airflow housing about a pivot axis and fixedly coupled to thebypass door such that the bypass door pivots about the pivot axis,wherein the second end portion of the bypass drive linkage is pivotallyconnected to the linear drive shaft of the actuator, wherein linearmovement of the linear drive shaft of the actuator translates torotational movement of the bypass door through the bypass drive linkage.

In one or more embodiments of the airflow control system as describedherein, the airflow control system may also include one or more supportsextending along the airflow housing, wherein the movable duct is movablycoupled to the one or more supports to move linearly along the one ormore supports, and a duct drive linkage extending between a first endportion movably coupled to the movable duct and a second end portionfixedly coupled to the first end portion of the bypass drive linkage,wherein rotational movement of the bypass drive linkage translates tolinear movement of the movable duct through the duct drive linkage dueto the one or more supports.

In one or more embodiments of the airflow control system as describedherein, the airflow control system may also include a filter assemblypositioned outside of the duct opening such that air passing from theduct opening to the engine intake must pass through the filter assemblybefore passing through the duct opening.

In one or more embodiments of the airflow control system as describedherein, the movable duct comprises a first movable duct and a secondmovable duct and the duct opening comprises a first duct opening and asecond duct opening, wherein the first and second movable ducts aremovably connected to the airflow housing to selectively allow or preventair passage through the first and second duct openings, respectively,and into the engine intake.

In one or more embodiments of the airflow control system as describedherein, the bypass door is pivotally coupled to the airflow housingwithin the bypass opening such that the bypass door pivots about a pivotaxis between a bypass open position to allow air passage through thebypass opening and a bypass closed position to prevent air passagethrough the bypass opening.

In one or more embodiments of the airflow control system as describedherein, the airflow housing comprises one or more supports, wherein themovable duct is movably coupled to the one or more supports to movelinearly along the one or more supports.

An illustrative aircraft may include an engine housing defining anengine intake to receive air flow, wherein the engine housing isconfigurable between a forward flight configuration and a hoverconfiguration, and an airflow control system as described herein,wherein the movable duct prevents air from passing through the ductopening and the bypass door allows air to pass through the bypassopening when in the bypass configuration, and wherein the movable ductallows air to pass through the duct opening and the bypass door preventsair passing through the bypass opening when in the filteredconfiguration.

An illustrative method of airflow control may include moving a bypassdoor from a bypass open position, allowing air to pass through a bypassopening, to a bypass closed position, preventing air from passingthrough the bypass opening, wherein an airflow housing defines anairflow passageway extending between the bypass opening and an intakeoutlet and the airflow housing also defines a duct opening positionedbetween the bypass opening and the intake outlet, wherein the intakeoutlet is in fluid communication with an engine intake such that airpasses from the bypass opening and/or the duct opening to the engineintake. The method may also include moving a movable duct from a ductclosed position, preventing air from passing through the duct opening,to a duct open position, allowing air to pass through the duct opening,wherein moving the bypass door from the bypass open position to thebypass closed position occurs simultaneously with moving the movableduct from the duct closed position to the duct open position. Further,the method may include moving the bypass door from the bypass closedposition to the bypass open position and moving the movable duct fromthe duct open position to the duct closed position, wherein moving thebypass door from the bypass closed position to the bypass open positionoccurs simultaneously with moving the movable duct from the duct openposition to the duct closed position.

In one or more embodiments of the method as described herein, moving thebypass door between the bypass open position and the bypass closedposition comprises transitioning through a bypass intermediate positionand moving the movable duct between the duct closed position and theduct open position comprises transitioning through a duct intermediateposition, wherein the bypass door transitions through the bypassintermediate position at the same time that the movable duct transitionsthrough the duct intermediate position, wherein air passes through thebypass opening when the bypass door is in the bypass intermediateposition and air passes through the duct opening when the movable ductis in the duct intermediate position.

In one or more embodiments of the method as described herein, moving thebypass door between the bypass open position and the bypass closedposition comprises pivoting the bypass door within the bypass openingabout a pivot axis.

In one or more embodiments of the method as described herein, moving thebypass door from the bypass open position to the bypass closed positionand moving the movable duct from the duct closed position to the ductopen position comprises moving an actuator from a first position to asecond position, and wherein moving the bypass door from the bypassclosed position to the bypass open position and moving the movable ductfrom the duct open position to the duct closed position comprises movingthe actuator from the second position to the first position.

In one or more embodiments of the method as described herein, the methodmay also include filtering air passing from the duct opening to theengine intake before passing through the duct opening.

The above summary is not intended to describe each embodiment or everyimplementation of the present disclosure. A more complete understandingwill become apparent and appreciated by referring to the followingdetailed description and claims taken in conjunction with theaccompanying drawings. In other words, these and various other featuresand advantages will be apparent from a reading of the following detaileddescription.

BRIEF DESCRIPTION OF THE DRAWING

The disclosure may be more completely understood in view of thefollowing description of illustrative embodiments in connection with theaccompanying drawings.

FIG. 1 is a perspective view of one illustrative embodiment of a vehicleincorporating an airflow control system as described herein;

FIG. 2A is a perspective view of one illustrative embodiment of anairflow control system with a bypass door in a bypass open position anda movable duct in a duct closed position;

FIG. 2B is an expanded view of the airflow control system of FIG. 2A;

FIG. 3A is a perspective view of another illustrative embodiment of anairflow control system with a bypass door in a bypass closed positionand a movable duct in a duct open position;

FIG. 3B is an expanded view of the airflow control system of FIG. 3A;

FIG. 4 is a cross-sectional view of the bypass door of FIG. 3A;

FIG. 5 is a perspective view of the airflow control system of FIG. 2Aincluding a filter assembly; and

FIG. 6 is a method of airflow control for an aircraft.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

In the following description of illustrative embodiments, reference ismade to the accompanying figures of the drawing, which form a parthereof, and in which are shown, by way of illustration, specificembodiments. It is to be understood that other embodiments may beutilized and structural changes may be made without departing from thescope of the present invention.

The disclosure herein includes illustrative embodiments of systems,apparatus, structures, and methods for an airflow control system for anaircraft including a bypass door and a movable duct. The bypass door andmovable duct may be movable to open and close a bypass opening and aduct opening, respectively, to provide a passageway for air to travelfrom the external environment to an engine intake. The bypass door andmovable duct may work together (e.g., be linked together and/or use asingle actuator/motor), but in opposite directions, to ensure that atleast one of the bypass opening and the duct opening are completely openor that both the bypass opening and the duct opening are at leastpartially open to provide the engine intake with air. Additionally, thebypass door and movable duct may be physically connected such thatmovement of one results in the movement of the other. For example, asthe movable duct opens, the bypass door closes, and when the movableduct closes, the bypass door opens. Further, external air must passthrough a filter assembly before passing through the duct opening to theengine intake, but air passing from the bypass opening to the engineintake does not pass through the filter assembly over the duct opening.As such, air passing through the bypass opening may enter the engineintake unfiltered.

The airflow control system described herein may be implemented onaircraft, or any other vehicle, that operates in multiple differentconfigurations. For example, in a first configuration (a filteredconfiguration), air passing to the engine intake may need to passthrough a filter assembly and, therefore, may travel through a filterassembly to the duct opening. In a second configuration (e.g., a bypassconfiguration), air passing to the engine intake may need to bypass thefilter assembly and proceed directly to the engine intake. Further, inthe first configuration in which air passes through the filter assembly,the external air may include much more debris and sediment, makingadditional filtering beneficial, than when in the second configuration.

In one or more embodiments, the airflow control system described hereinmay be implemented on a vertical take-off and landing (VTOL) aircraft(e.g., a V-22 aircraft) that operates in both a forward flightconfiguration and a hover configuration. In other words, the VTOLaircraft may be configured to adjust the orientation of the enginesand/or rotor blades to combine the functionality of a conventionalhelicopter with the long-range and high-speed abilities of a turbopropaircraft. When the aircraft is in a hover configuration (e.g., duringtake-off or landing), the increased downward wind speed may produceadditional debris and sediment that could affect the engine intake ifnot filtered out of the intake air. Therefore, the airflow controlsystem described herein opens the duct opening, which requires airpassage through a filter assembly before entering the duct opening tothe engine intake, and closes the bypass opening to prevent undesireddebris and sediment from entering the engine intake (e.g., in thefiltered configuration). On the other hand, when the aircraft is in aforward flight configuration (e.g., while cruising), the forward-facingbypass opening may be opened to maximize the amount of air passing tothe engine intake and the duct opening may be closed to prevent leakageor back draft of air passing between the bypass opening and the engineintake (e.g., in the bypass configuration). For example, having the ductopening closed prevents excess air from exiting back out through thefilters (e.g., the outer mold line of the aircraft) and preventsspillage (which causes drag and reduces aircraft performance and range).Because the aircraft is at a cruising speed and altitude, the airflowcontrol system may not necessarily require air to pass through a filterassembly, as may be needed in the hover configuration. It is noted that,while the forward flight configuration may be described in conjunctionwith the bypass configuration and the hover configuration may bedescribed in conjunction with the filtered configuration, the aircraftmay operate such that the airflow control system may, if desired, be inthe bypass configuration when the aircraft is in the hover configurationand the airflow control system may, if desired, be in the filteredconfiguration when the aircraft is in the forward flight configuration.

One illustrative embodiment of an airflow control system within avehicle 10 is depicted in FIG. 1. Specifically, FIG. 1 illustrates aV-22 Osprey aircraft, however, the airflow control system describedherein may be applied to airflow systems of a variety of vehicles and/orequipment. For example, the airflow control system may be implementedwithin helicopters, fixed wing aircraft, etc.

The vehicle 10 may include an engine housing 14 that is configurablebetween a forward flight configuration (not shown) and a hoverconfiguration (e.g., as shown in FIG. 1). The vehicle 10 may include anairflow control system 100 as described herein. In some embodiments, theairflow control system 100 may be retrofitted onto existing componentsor structure of a vehicle. The airflow control system 100 may include aninlet to receive air from the external environment to feed the engineduring operation. For example, as described further herein, the airflowcontrol system 100 may include a bypass opening 122 proximate a frontend of the engine housing 14 and may include a duct opening (not shown),which is covered by a filter assembly 104 in FIG. 1. As describedherein, air from the external environment may pass through the airflowcontrol system 100 through one or both the bypass opening 122 and theduct opening/filter assembly 104.

FIGS. 2A and 3A depict an illustrative airflow control system 100 with abypass door 140 and a movable duct 160 in two different configurations.The airflow control system 100 may include an air housing 120 definingan airflow passageway 125 extending between a bypass opening 122 and anintake outlet 124 (e.g., the intake outlet 124 is shown in FIG. 3A). Theairflow housing 120 may further define a duct opening 126 (e.g., asshown in FIG. 3A in front of the intake outlet 124) positioned betweenthe bypass opening 122 and the intake outlet 124. In other words, theduct opening 126 may be positioned such that air passes from the ductopening 126 to the intake outlet 124 without passing through the bypassopening 122. The intake outlet 124 may be in fluid communication with anengine intake 12 of the aircraft 10 such that air passes from the bypassopening 122 and/or the duct opening 126 to the engine intake 12 throughthe intake outlet 124.

The airflow control system 100 may also include a bypass door 140movably connected to the airflow housing 120 to selectively allow orprevent air passage through the bypass opening 122 and into the engineintake 12. In other words, the bypass door 140 may move to a positionsuch that the bypass opening 122 may be generally unobstructed such thatair can freely pass through the bypass opening 122. Also, the bypassdoor 140 may move to another position such that the bypass opening 122may be completely or almost completely obstructed such that air cannotpass through the bypass opening 122. The bypass door 140 andcorresponding bypass opening 122 may be any suitable shape and size,e.g., a perimeter of the bypass door 140 may substantially match aperimeter of the bypass opening 122 to, e.g., prevent air from passingthrough the bypass opening 122 when the bypass door 140 is closed. Insome embodiments, the bypass door 140 may define a thinner profile(e.g., a reduced thickness) to reduce the amount of air resistance whenthe bypass door 140 is open (e.g., as shown in FIG. 2A).

In one or more embodiments, the bypass door 140 may be pivotally coupledto the airflow housing 120 within the bypass opening 122. As such, thebypass door 140 may pivot about a pivot axis 141 to open or close thebypass opening 122. The pivot axis 141 may be located anywhere on theairflow housing 120 along the bypass opening 122. For example, the pivotaxis 141 may be located at the top of the bypass opening 122, the bottomof the bypass opening 122, or anywhere therebetween. Also, the pivotaxis 141 may be oriented vertically or horizontally. As shown in FIG. 4,the pivot axis 141 is located proximate the middle of the bypass opening122 along a horizontal orientation. When the bypass door 140 is pivotedin a bypass closed position (e.g., as shown in FIG. 3A), the bypass door140 coincides with the edges of the bypass opening 122 and may beperpendicular to the direction of airflow through the bypass opening 122(e.g., to maximize the surface area of the bypass door 140 blocking theair). When the bypass door 140 is pivoted in a bypass open position(e.g., as shown in FIG. 2A), the bypass door may be generally parallelto the direction of airflow through the bypass opening 122 (e.g., tominimize the profile of the bypass door 140 that impedes the air flowthrough the bypass opening 122).

Further, the airflow control system 100 may also include a movable duct160 (e.g., a sliding duct) movably (e.g., slidably) connected to theairflow housing 120 to selectively allow or prevent air passage throughthe duct opening 126 and into the engine intake 12. In other words, themovable duct 160 may move to a position such that the duct opening 126may be generally unobstructed such that air can freely pass through theduct opening 126. Also, the movable duct 160 may move to anotherposition such that the duct opening 126 may be completely or almostcompletely obstructed such that air cannot pass through the duct opening126.

The movable duct 160 and the duct opening 126 may take any correspondingshape and/or size. For example, as illustrated in FIGS. 2A and 3A, theduct opening 126 may define a semicircular shape including two separateopenings (only the near duct opening is visible). The airflow housing120 may include a bottom portion (e.g., a drain strut) extending betweenthe bypass opening 122 and the intake outlet 124 that separates the twoduct openings and be closed such that air cannot pass through the bottomportion. Further, the movable duct 160 may include multiple portions(e.g., a first movable duct and a second movable duct) that are movableto cover the corresponding duct opening 126. The second movable duct andsecond duct opening are not illustrated in FIGS. 2A and 3A, but aregenerally mirror images of the movable duct 160 and duct opening 126 asshown.

The movable duct 160 may be movably connected to the airflow housing 120in any suitable way. For example, the airflow control system 100 mayinclude one or more supports 110 (e.g., support tubes) extending alongthe airflow housing 120 that couple the movable duct 160 to the airflowhousing 120. For example, the one or more supports 110 may be coupled tothe airflow housing 120 (e.g., using brackets) and the movable duct 160may be movably coupled to the one or more supports 110. The airflowcontrol system 100 may include any number of supports 110. Specifically,the airflow control system 100 illustrated in FIGS. 2A and 3A includestwo supports 110 (for each movable duct 160). The movable duct 160 maybe movably coupled to the one or more supports 110 to move the movableduct 160 linearly along the one or more supports 110 (e.g., along linearbearings). Further, the one or more supports 110 may include a stoppingmember that is configured to restrict movement of the movable duct 160along the one or more supports 110 (e.g., in a duct open position or aduct closed position). In other words, the stopping member may preventthe movable duct 160 from moving too far along the one or more supports110.

The airflow control system 100 may also include a filter assembly 104positioned outside of the duct opening 126 as illustrated in FIG. 5. Thefilter assemblies 104 used in one or more embodiments of the airflowcontrol system 100 may include one or more filters configured to providefiltering for air passing through the duct openings 126. The depictedillustrative embodiments of the filter assembly 104 includes twoseparate filters. Other embodiments may include only one (e.g., larger)filter or three or more filters as needed. The filter assembly 104 maybe positioned such that air passing from the duct opening 126 to theengine intake 12 must pass through the filter assembly 104 beforepassing through the duct opening 126.

Each of the bypass door 140 and the movable duct 160 may be configuredto open and close the corresponding opening (e.g., bypass opening 122and duct opening 126, respectively). For example, the movable duct 160may be movable between a duct open position (e.g., as shown in FIG. 3A)to allow air to pass through the duct opening 126 (and to the engineintake 12) and a duct closed position (e.g., as shown in FIG. 2A) toprevent air from passing through the duct opening 126 (and to the engineintake 12). Due to the positioning of the filter assembly 104 (e.g., asshown in FIG. 5), air passing through the duct opening 126 when themovable duct 160 is in the duct open position must first pass throughthe filter assembly 104.

Further, the bypass door 140 may be movable between a bypass openposition (e.g., as shown in FIG. 2A) to allow air to pass through thebypass opening 122 (and to the engine intake 12) and a bypass closedposition (e.g., as shown in FIG. 3A) to prevent air from passing throughthe bypass opening 122 (and to the engine intake 12). It is noted that,preventing air from passing through a particular opening does notnecessarily equal complete closure of the opening, but rather indicatesthat air is restricted from passing through the opening because the sizeof the opening is significantly reduced as compared to its size when inthe open configuration. In one or more embodiments, the bypass door 140or movable duct 160 may reduce the size of the opening (e.g., when“closed”) by 50% or more, 60% or more, 70% or more, 80% or more, 90% ormore, etc.

In one or more embodiments, the bypass door 140 and the movable duct 160may be configured to move in conjunction or together with one another.In other words, movement of the movable duct 160 may be interrelated orlinked to movement of the bypass door 140. Specifically, the movableduct 160 and the bypass door 140 may move in opposite directions (e.g.,open/closed and closed/open) from one another at the same time.

For example, the movable duct 160 may move from the duct open positionto the duct closed position when the bypass door 140 moves from thebypass closed position to the bypass open position. Also, the movableduct 160 may move from the duct closed position to the duct openposition when the bypass door 140 moves from the bypass open position tothe bypass closed position.

Due to the relationship between the movement of each of the bypass door140 and the movable duct 160, one may be closed while the other is openand vice versa. For example, the movable duct 160 may be in the ductopen position when the bypass door 140 is in the bypass closed position(e.g., as shown in FIG. 3A). Specifically, FIG. 3A illustrates theairflow control system 100 in the filtered configuration so that thebypass opening 122 is closed (e.g., preventing airflow through thebypass opening 122) and airflow is forced to pass through the open ductopenings 126 (and, thus, the filter assembly 104). The aircraft may bein either of the forward flight configuration or the hover configurationwhen the airflow control system is in the filtered configuration.

For example, if the aircraft enters icing conditions, the bypass door140 may be closed to protect ice from accruing inside the passageway125, which could then break loose and potentially damage the engine.With air passing through the duct openings 126, ice would be less likelyto reach the engine. Also, for example, if the aircraft enters asandstorm, flies over forest fires, flies through volcanic ash, etc.,the filter assembly 104 would provide filtered air with the bypass door140 closed and the movable ducts 160 open. Even further, for example, inthe filtered configuration, the filter assembly 104 may protect theengine from salt damage if the aircraft is hovering low over salt water(e.g., salt entering the engine may cause rapid engine deterioration).

Also, the movable duct 160 may be in the duct closed position when thebypass door 140 is in the bypass open position (e.g., as shown in FIG.2A). Specifically, FIG. 2A illustrates the airflow control system 100 inthe bypass configuration so that air flows through the bypass opening122, and the closed duct openings 126 block air from the filter assembly104, to the engine intake 12. The closing of the movable ducts 160 andthe opening of the bypass door 140 may occur in connection with (e.g.,in response to) the vehicle 10 entering the forward flight configurationor the hover configuration, and vice versa. By maintaining the movableduct 160 in the duct closed position when the bypass door 140 is in thebypass open position, the movable duct 160 may contain airflow passingfrom the bypass opening 122 to the engine intake 12. Blocking airflowentering the airflow passageway 125, through the bypass opening 122,from leaving the airflow passageway 125, through the duct opening 126,may help reduce outflow and spillage, which may reduce aircraft drag.Additionally, the closed movable ducts 160 (e.g., in the duct closedposition) may pressurize the bypass opening 122 to help mitigate enginedistortion. The aircraft may be in either of the forward flightconfiguration or the hover configuration when the airflow control systemis in the bypass configuration.

In one or more embodiments, the movement of the movable duct 160 and thebypass door 140 may be configured such that at least one of the bypassopening 122 and the duct opening 126 may always be at least partiallyopen. For example, because the movable duct 160 and the bypass door 140may be configured to move together such that the movable duct 160 movesfrom open to closed while the bypass door 140 moves from closed to open,and vice versa, at least one of the bypass door 140 and the movable duct160 may be starting to open when the other is starting to close (e.g.,at least one may be always partially open). As a result of thisrelationship between the movable duct 160 and the bypass door 140, theairflow control system 100 may, when operating as designed, never be inposition that the bypass opening 122 and the duct opening 126 are bothclosed at the same time and prevent airflow to the engine. For example,if an actuator that moves both the bypass door 140 and the movable duct160 became inoperable, airflow would still be allowed to pass to theengine intake 12 (e.g., through at least a portion of the bypass opening122 and/or the duct opening 126) regardless of whether the enginehousing 14 is, e.g., in the forward flight configuration or the hoverconfiguration, or if the airflow control system 100 is in the filteredconfiguration, bypass configuration, or somewhere therebetween (e.g.,such that there will always be air flow to the engine).

In one or more embodiments, the airflow control system 100 may includean actuator 180, as shown in FIGS. 2B, 3B, and 4, configured to moveboth the bypass door 140 and the movable duct 160. For example, in anairflow control system having limited control channels and limitedadditional power available (e.g., no additional current draw), a singleactuator may be used. In other embodiments, the airflow control system100 may include a first actuator configured to move the bypass door 140and a second actuator configured to move the movable duct 160 (e.g., thefirst actuator is different than the second actuator). The actuator 180may be coupled to the airflow housing 120 in a variety of differentways. For example, the actuator 180 may be pivotally coupled to theairflow housing 120 to allow for the actuator 180 to pivot through anarc while moving the bypass door 140 as described further herein. Theactuator 180 may include a linear drive shaft 182 configured to extendand retract (from a housing of the actuator 180) in a linear direction.It is noted that the actuator 180 may be any suitable actuation device.For example, the actuator 180 may be a hydraulic motor, an electricmotor with a gearhead and screw drive, a pulley and cable, a rack andpinion, etc.

The airflow control system 100 may also include a bypass drive linkage150 extending between a first end portion 152 and a second end portion154. The first end portion 152 of the bypass drive linkage 150 may bepivotally connected to the airflow housing 120 about a pivot axis 141and fixedly coupled to the bypass door 140 such that the bypass door 140pivots about the pivot axis 141 (e.g., between the bypass open positionand the bypass closed position). The second end portion 154 of thebypass drive linkage 150 may be pivotally connected to the linear driveshaft 182 of the actuator 182. Linear movement of the linear drive shaft182 of the actuator 180 may translate to rotational movement of thebypass door 140 through the bypass drive linkage 150. For example, asthe linear drive shaft 182 extends along the linear direction, thelinear drive shaft 182 forces the second end portion 154 of the bypassdrive linkage 150 through an arc about the pivot axis 141. This pivotabout the pivot axis 141 of the second end portion 154 of the bypassdrive linkage 150 then rotates the bypass door 140 at the same ratebecause the bypass drive linkage 150 is fixedly coupled to the bypassdoor 140.

Further, the airflow control system 100 may include a duct drive linkage170 extending between a first end portion 172 movably coupled to themovable duct 140 (e.g., contained within a linkage housing 178 as shownin FIGS. 2B and 3B) and a second end portion 174 fixedly coupled to thefirst end portion 152 of the bypass drive linkage 150. Rotationalmovement of the bypass drive linkage 150 may then translate to linearmovement of the movable duct 140 through the duct drive linkage 170 dueto the one or more supports 110. In other embodiments, the duct drivelinkage 170 and the bypass drive linkage 150 may include any suitableconfiguration or mechanism (e.g., whether a linkage or some othermechanism) to transfer motion as described herein.

For example, the duct drive linkage 170 includes a two-bar linkageextending between the movable duct 160 and the bypass drive linkage 150.When the bypass drive linkage 150 rotates in a first direction, the ductdrive linkage 170 folds to decrease the distance between the bypass door140 and the movable duct 160—moving the movable duct 160 away from theduct opening 126 (e.g., as shown in FIG. 3B). When the bypass drivelinkage 150 rotates in a second direction opposite the first direction,the duct drive linkage 170 extends to increase the distance between thebypass door 140 and the movable duct 160—moving the movable duct 160towards the duct opening 126 (e.g., as shown in FIG. 2B). The movableduct 160 may extend along a linear path, and the duct drive linkage 170may be controlled (e.g., expanding and retracting), because of the oneor more supports 110. In other words, the movable duct 160 is forced tofollow the linear path provided by the one or more supports 110.Additionally, in such embodiments including a second movable duct on theopposite side from the movable duct 160, the torque from rotating thebypass door 140 may pass from the actuator 180 side to the secondmovable duct side (e.g., as shown in FIG. 4) and move the second movableduct similar to the movable duct 160. Further, the bypass drive linkage150 and the duct drive linkage 170 may include splined drive arms andshafts (e.g., to more easily install and disassemble the system in casethe bypass door 140 needs to be replaced).

Although the bypass door 140 rotates between its open and closedpositions and the movable ducts 160 translate between their open andclosed positions in the depicted illustrative embodiments, one or morealternative embodiments of the airflow control systems 100 as describedherein may operate through any motion or motions effective to open andclose the corresponding opening. For example, the bypass doors inalternative systems may translate between their open and closedpositions and/or the movable ducts may rotate between their open andclosed positions. In still other embodiments, combinations of rotationaland translational movements may be used to move bypass doors and/ormovable ducts.

One illustrative embodiment of a method 600 of airflow control for avehicle is illustrated in FIG. 6. The method 600 may include moving 610a bypass door (e.g., bypass door 140) from a bypass open position (e.g.,allowing air to pass through a bypass opening) to a bypass closedposition (e.g., preventing air from passing through the bypass opening).The method 600 may also include moving 620 a movable duct (e.g., movableduct 160) from a duct closed position (e.g., preventing air from passingthrough the duct opening) to a duct open position (e.g., allowing air topass through the duct opening). The moving 610 of the bypass door fromthe bypass open position to the bypass closed position may occursimultaneously with the moving 620 of the movable duct from the ductclosed position to the duct open position.

Further, the method 600 may include moving 630 the bypass door from thebypass closed position to the bypass open position and moving 640 themovable duct from the duct open position to the duct closed position.The moving 630 of the bypass door from the bypass closed position to thebypass open position may occur simultaneously with the moving 640 of themovable duct from the duct open position to the duct closed position.

In one or more embodiments, moving the bypass door between the bypassopen position and the bypass closed position may include transitioningthrough a bypass intermediate position and moving the movable ductbetween the duct closed position and the duct open position may includetransitioning through a duct intermediate position. The bypass door maytransition through the bypass intermediate position at the same timethat the movable duct transitions through the duct intermediateposition. This transition of each of the bypass door and the movableduct may help to ensure that at least one of the bypass opening and theduct opening are always at least partially open. For example, air maypass through the bypass opening when the bypass door is in the bypassintermediate position and air may pass through the duct opening when themovable duct is in the duct intermediate position.

In one or more embodiments, moving the bypass door from the bypass openposition to the bypass closed position and moving the movable duct fromthe duct closed position to the duct open position may include moving alinear drive shaft of an actuator from a first position (e.g., aposition retracted towards the housing of the actuator) to a secondposition (e.g., a position extended away from the housing of theactuator). Further, moving the bypass door from the bypass closedposition to the bypass open position and moving the movable duct fromthe duct open position to the duct closed position may include movingthe linear drive shaft of the actuator from the second position to thefirst position. The first position and the second position may belocated (e.g., the actuator and/or linear drive shaft thereof may bepositioned and configured to move in any suitable way) such that thebypass door and the movable duct move as described herein.

In the preceding description, reference is made to the accompanying setof drawings that form a part hereof and in which are shown by way ofillustration several specific embodiments. It is to be understood thatother embodiments are contemplated and may be made without departingfrom (e.g., still falling within) the scope of the present disclosure.The preceding detailed description, therefore, is not to be taken in alimiting sense. All scientific and technical terms used herein havemeanings commonly used in the art unless otherwise specified. Thedefinitions provided herein are to facilitate understanding of certainterms used frequently herein and are not meant to limit the scope of thepresent disclosure.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsare to be understood as being modified in all instances by the term“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the foregoing specification and attached claimsare approximations that can vary depending upon the desired propertiessought to be obtained by those skilled in the art utilizing theteachings disclosed herein.

The recitation of numerical ranges by endpoints includes all numberssubsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3,3.80, 4, and 5) and any range within that range.

As used in this specification and the appended claims, the singularforms “a”, “an”, and “the” encompass embodiments having pluralreferents, unless the content clearly dictates otherwise. As used inthis specification and the appended claims, the term “or” is generallyemployed in its sense including “and/or” unless the content clearlydictates otherwise.

As used herein, “have”, “having”, “include”, “including”, “comprise”,“comprising” or the like are used in their open-ended sense, andgenerally mean “including, but not limited to”. It will be understoodthat “consisting essentially of”, “consisting of”, and the like aresubsumed in “comprising,” and the like.

It is noted that terms such as “top”, “bottom”, “above, “below”, etc.may be used in this disclosure. These terms should not be construed aslimiting the position or orientation of a structure, but should be usedas providing spatial relationship between the structures.

All references and publications cited herein are expressly incorporatedherein by reference in their entirety into this disclosure, except tothe extent they may directly contradict this disclosure. Althoughspecific embodiments have been illustrated and described herein, it willbe appreciated by those of ordinary skill in the art that a variety ofalternate and/or equivalent implementations can be substituted for thespecific embodiments shown and described without departing from thescope of the present disclosure. This application is intended to coverany adaptations or variations of the specific embodiments discussedherein. Therefore, it is intended that this disclosure be limited onlyby the claims and the equivalents thereof. The disclosed embodiments arepresented for purposes of illustration and not limitation.

What is claimed:
 1. An airflow control system for a vehicle comprising:an airflow housing defining an airflow passageway extending between abypass opening and an intake outlet, wherein the airflow housing furtherdefines a duct opening positioned between the bypass opening and theintake outlet, wherein the intake outlet is in fluid communication withan engine intake of the vehicle such that air passes from the bypassopening and/or the duct opening to the engine intake; a movable ductmovably connected to the airflow housing to selectively allow or preventair passage through the duct opening and into the engine intake; abypass door movably connected to the airflow housing to selectivelyallow or prevent air passage through the bypass opening and into theengine intake; a filter assembly positioned outside of the duct openingsuch that air passing from the duct opening to the engine intake mustpass through the filter assembly before passing through the ductopening; and a single actuator configured to move both the bypass doorand the movable duct.
 2. The airflow control system of claim 1, whereinmovement of the movable duct is interrelated to movement of the bypassdoor.
 3. The airflow control system of claim 1, wherein the movable ductis movable between a duct open position to allow air to pass through theduct opening and a duct closed position to prevent air from passingthrough the duct opening, and wherein the bypass door is movable betweena bypass open position to allow air to pass through the bypass openingand a bypass closed position to prevent air from passing through thebypass opening.
 4. The airflow control system of claim 3, wherein themovable duct moves from the duct open position to the duct closedposition when the bypass door moves from the bypass closed position tothe bypass open position, and wherein the movable duct moves from theduct closed position to the duct open position when the bypass doormoves from the bypass open position to the bypass closed position. 5.The airflow control system of claim 3, wherein the movable duct is inthe duct open position when the bypass door is in the bypass closedposition, and wherein the movable duct is in the duct closed positionwhen the bypass door is in the bypass open position.
 6. The airflowcontrol system of claim 1, wherein at least one of the bypass openingand the duct opening is always at least partially open.
 7. The airflowcontrol system of claim 1, further comprising: the single actuatorcoupled to the airflow housing and comprising a linear drive shaftconfigured to extend and retract in a linear direction, and a bypassdrive linkage extending between a first end portion and a second endportion, wherein the first end portion of the bypass drive linkage ispivotally connected to the airflow housing about a pivot axis andfixedly coupled to the bypass door such that the bypass door pivotsabout the pivot axis, wherein the second end portion of the bypass drivelinkage is pivotally connected to the linear drive shaft of the singleactuator, wherein linear movement of the linear drive shaft of thesingle actuator translates to rotational movement of the bypass doorthrough the bypass drive linkage.
 8. The airflow control system of claim7, further comprising: one or more supports extending along the airflowhousing, wherein the movable duct is movably coupled to the one or moresupports to move linearly along the one or more supports, and a ductdrive linkage extending between a first end portion movably coupled tothe movable duct and a second end portion fixedly coupled to the firstend portion of the bypass drive linkage, wherein rotational movement ofthe bypass drive linkage translates to linear movement of the movableduct through the duct drive linkage due to the one or more supports. 9.The airflow control system of claim 1, wherein the movable ductcomprises a first movable duct and a second movable duct and the ductopening comprises a first duct opening and a second duct opening,wherein the first and second movable ducts are movably connected to theairflow housing to selectively allow or prevent air passage through thefirst and second duct openings, respectively, and into the engineintake.
 10. The airflow control system of claim 1, wherein the bypassdoor is pivotally coupled to the airflow housing within the bypassopening such that the bypass door pivots about a pivot axis between abypass open position to allow air passage through the bypass opening anda bypass closed position to prevent air passage through the bypassopening.
 11. The airflow control system of claim 1, wherein the airflowhousing comprises one or more supports, wherein the movable duct ismovably coupled to the one or more supports to move linearly along theone or more supports.
 12. An aircraft comprising: an engine housingdefining an engine intake to receive air flow, wherein the enginehousing is configurable between a forward flight configuration and ahover configuration; and an airflow control system comprising: anairflow housing defining an airflow passageway extending between abypass opening and an intake outlet, wherein the airflow housing furtherdefines a duct opening positioned between the bypass opening and theintake outlet, wherein the intake outlet is in fluid communication withan engine intake of the vehicle such that air passes from the bypassopening and/or the duct opening to the engine intake; a movable ductmovably connected to the airflow housing to selectively allow or preventair passage through the duct opening and into the engine intake; abypass door movably connected to the airflow housing to selectivelyallow or prevent air passage through the bypass opening and into theengine intake; a filter assembly positioned outside of the duct openingsuch that air passing from the duct opening to the engine intake mustpass through the filter assembly before passing through the ductopening; and a single actuator configured to move both the bypass doorand the movable duct, wherein the movable duct prevents air from passingthrough the duct opening and the bypass door allows air to pass throughthe bypass opening when in the forward flight configuration, and whereinthe movable duct allows air to pass through the duct opening and thebypass door prevents air passing through the bypass opening when in thehover configuration.
 13. A method of airflow control comprising: movinga bypass door from a bypass open position, allowing air to pass througha bypass opening, to a bypass closed position, preventing air frompassing through the bypass opening, wherein an airflow housing definesan airflow passageway extending between the bypass opening and an intakeoutlet and the airflow housing also defines a duct opening positionedbetween the bypass opening and the intake outlet, wherein the intakeoutlet is in fluid communication with an engine intake such that airpasses from the bypass opening and/or the duct opening to the engineintake; moving a movable duct from a duct closed position, preventingair from passing through the duct opening, to a duct open position,allowing air to pass through the duct opening, wherein both moving thebypass door from the bypass open position to the bypass closed positionand moving the movable duct from the duct closed position to the ductopen position comprises moving a single actuator from a first positionto a second position; moving the bypass door from the bypass closedposition to the bypass open position; and moving the movable duct fromthe duct open position to the duct closed position, wherein both movingthe bypass door from the bypass closed position to the bypass openposition and moving the movable duct from the duct open position to theduct closed position comprises moving the single actuator from thesecond position to the first position.
 14. The method of claim 13,wherein moving the bypass door between the bypass open position and thebypass closed position comprises transitioning through a bypassintermediate position and moving the movable duct between the ductclosed position and the duct open position comprises transitioningthrough a duct intermediate position, wherein the bypass doortransitions through the bypass intermediate position at the same timethat the movable duct transitions through the duct intermediateposition, wherein air passes through the bypass opening when the bypassdoor is in the bypass intermediate position and air passes through theduct opening when the movable duct is in the duct intermediate position.15. The method of claim 13, wherein moving the bypass door between thebypass open position and the bypass closed position comprises pivotingthe bypass door within the bypass opening about a pivot axis.
 16. Themethod of claim 13, further comprising filtering air passing from theduct opening to the engine intake before passing through the ductopening.
 17. The method of claim 13, wherein the air passing from theduct opening to the engine intake must pass through a filter assemblypositioned outside of the duct opening before passing through the ductopening.